Optical investigation of InGaN GaN multiple quantum wells

Optical investigation was performed on InGaN/GaN multiple quantum well (MQW) structures with different well thicknesses. At low temperature, the excitation power dependence of the photoluminescence (PL) emission energy of a MQW with 5 nm well thickness was found to be different from that of a MQW with 2.5 nm well thickness. Their temperature dependence of the optical behaviors including the PL line shapes and the internal quantum efficiencies also showed distinct features. The optical behaviors of the quantum well with a thickness above 2.5 nm can be explained by a model based on the formation of self-organized small In-rich regions, rather than by the piezoelectric field-induced quantum-confined Stark effect. (C) 1999 American Institute of Physics. [S0003-6951(99)01521-1].